Q3 of 48 Page 126

The mean of nine numbers is 77. If one more number is added to it than the mean increases by 5. Find the number added in the data.

We know that



⇒ Sum of observations = Mean × Total number of observations


⇒ Sum of 9 numbers = 9×77 ..(1)


And Mean increases by 5 when one more number is also added to it.



⇒ New number + 9×77 = 82 × 5


⇒ New number =820 – 693 = 127


More from this chapter

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1

From following table, what is the cumulative frequency of less than type for the class 30-40?

 2

The mean salary of 20 workers is Rs.10, 250. If the salary of office superintendent is added, the mean will increase by Rs.750. Find the salary of the office superintendent.

 4

The monthly maximum temperature of a city is given in degree celcius in the following data. By taking suitable classes, prepare the grouped frequency distribution table

29.2, 29.0, 28.1, 28.5, 32.9, 29.2, 34.2, 36.8, 32.0, 31.0,


30.5, 30.0, 33, 32.5, 35.5, 34.0, 32.9, 31.5, 30.3, 31.4,


30.3, 34.7, 35.0, 32.5, 33.5, 29.0, 29.5, 29.9, 33.2, 30.2


From the table, answer the following questions.


i. For how many days the maximum temperature was less than 34oC?


ii. For how many days the maximum temperature was 34oC or more than 34oC?

 5

If the mean of the following data is 20.2, then find the value of p.